Multistage centrifugal chopper pump

Abstract

A centrifugal pump has a bladed impeller rotating in the bowl of the pump casing. The inlet side of the pump bowl is closed by an intake plate. A hub rotated with the impeller extends through the intake plate, generally axially outward from the impeller blades. The hub has an abrupt projection in close cutting relationship with at least a portion of the intake plate as the impeller is rotated.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: 
     
       1. In a centrifugal pump having a bladed impeller rotatable about an axis, a pump casing including a bowl receiving the impeller blades and having an inlet side for intake of material into the pump bowl, the pump casing including an intake plate extending across the inlet side of the pump bowl, the improvement comprising a hub rotated with the impeller and extending through the intake plate, generally axially outward from the impeller blades, said hub having an abrupt projection in close cutting relationship with at least a portion of said intake plate as the impeller is rotated. 
     
     
       2. In the pump defined in claim 1, the intake plate including at least one radially extending rib having an inner end adjacent to the hub, said inner end of said rib being in close cutting relationship with the abrupt projection of the hub as the hub is rotated. 
     
     
       3. In the pump defined in claim 1, the improvement further comprising an external cutter positioned at the opposite side of the intake plate from the impeller blades, said external cutter being rotated with the impeller and the hub and having a portion in close cutting relationship to at least a portion of the intake plate.